Photonic platforms are an excellent setting for quantum technologies as weak photon–environment coupling ensures long coherence times. The second key ingredient for quantum photonics is interactions between photons, which can be provided by optical nonlinearities in the form of cross-phase modulation. This approach underpins many proposed applications in quantum optics1,2,3,4,5,6,7 and information

Ultra-narrow optical spectral features resulting from highly dispersive light–matter interactions are essential for a broad range of applications such as spectroscopy, slow-light and high-precision sensing. Features approaching sub-megahertz or, equivalently, Q-factors up to one billion and beyond, are challenging to obtain in solid-state systems, ultimately limited by loss. We present a novel approach

High-harmonics spectroscopy reveals the closure of the bandgap between adjacent conduction bands in solids driven by high-intensity laser fields, providing insight into light-driven modifications of band structures

The strongly temperature-dependent band-edge absorption from gallium arsenide enables an optical thermometer with nanokelvin temperature resolution and microscale spatial resolution.

Toroidal vortices, also known as vortex rings, are whirling, closed-loop disturbances that form a characteristic ring shape in liquids and gases and propagate in a direction that is perpendicular to the plane of the ring. They are well-studied structures and commonly found in various fluid and gas flow scenarios in nature, for example in the human heart, underwater air bubbles and volcanic eruptions1

Ultrahigh-resolution thermometry is critical for future advances in bio-calorimetry1,2, sensitive bolometry for sensing3 and imaging4, as well as for probing dissipation in a range of electronic5, optoelectronic6 and quantum devices7. In spite of recent advances in the field8,9,10,11, achieving high-resolution measurements from microscale devices at room temperature remains an outstanding challenge

Spintronic devices, by harnessing the spin degree of freedom, are expected to outperform charge-based devices in terms of energy efficiency and speed of operation. The use of an electric field to control spin at room temperature has been pursued for decades. A major hurdle that has contributed to the slow progress in this regard is the dilemma between effective control and strong spin relaxation. For

Intense light–matter interactions have revolutionized our ability to probe and manipulate quantum systems at sub-femtosecond timescales1, opening routes to the all-optical control of electronic currents in solids at petahertz rates2,3,4,5,6,7. Such control typically requires electric-field amplitudes in the range of almost volts per angstrom, when the voltage drop across a lattice site becomes comparable

A heat-powered emitter can sometimes exceed the Planck thermal-emission limit. We clarify when such super-Planckian emission is possible, arguing that far-field super-Planckian emission requires a distribution of energy that is not consistent with a unique temperature, and therefore the process should not be called ‘thermal emission’.

Non-line-of-sight (NLOS) imaging is a rapidly developing research direction that has significant applications in autonomous vehicles, remote sensing and other areas. Existing NLOS methods primarily depend on time-gated measurements and sophisticated signal processing to extract information from scattered light. Here we introduce a method that directly manipulates light to counter the wall’s scattering

Solitons attract a great deal of interest in many fields, ranging from optics to fluid mechanics, cosmology, particle physics and condensed matter. However, solitons of these very different types rarely coexist and interact with each other. Here we develop a system that hosts optical solitons coexisting with topological solitonic structures localized in the molecular alignment field of a soft birefringent

High-power laser delivery with near-diffraction-limited beam quality is typically limited to tens of metres distances by nonlinearity-induced spectral broadening inside the glass core of delivery fibres. Anti-resonant hollow-core fibres offer not only orders-of-magnitude lower nonlinearity but also loss and modal purity comparable to conventional beam-delivery fibres. Using a single-mode hollow-core

A novel class of programmable integrated photonic circuits has emerged over the past years, strongly driven by approaches to tackle unsolved computing problems in the optical domain. Photonic neuromorphic and quantum computing are examples of optical systems implemented in complex photonic circuits, which are reconfigured before and during operation. However, a key building block to enable efficient

Stacking order in van der Waals materials determines the coupling between atomic layers and is therefore the key to materials’ properties. Recently, ferroelectricity, a phenomenon exhibiting reversible spontaneous electrical polarization, has been observed in zero-degree aligned van der Waals structures. In these artificial stacks, the single-domain size is limited by angle misalignment. Here we show

Tailoring the electric-field waveform of ultrashort light pulses forms the basis for controlling nonlinear optical phenomena on their genuine, attosecond timescale. Here we extend waveform control from the visible and near-infrared—where it was previously demonstrated—to the mid-infrared spectral range. Our approach yields single-cycle infrared pulses over several octaves for the first time. Sub-10-fs

Multiple exciton generation (MEG), the generation of multiple electron–hole pairs from a single high-energy photon, can enhance the photoconversion efficiency in several technologies including photovoltaics, photon detection and solar-fuel production1,2,3,4,5,6. However, low efficiency, high photon-energy threshold and fast Auger recombination impede its practical application1,7. Here we achieve enhanced

Quantum-dot light-emitting diodes (QD-LEDs) promise a new generation of efficient, low-cost, large-area and flexible electroluminescent devices. However, the inferior performance of green and blue QD-LEDs compared with their red counterpart is hindering the commercialization of QD-LEDs in display and solid-state lighting applications. Here we demonstrate green and blue QD-LEDs with ~100% conversion

Nature Photonics spoke to Hillel Adesnik from UC Berkeley about the benefits of using photonic techniques in optogenetics and the key challenges laying ahead.

A single-pass free electron laser operating at 0.16 THz with an energy efficiency of ~10% promises compact and high-power sources in the terahertz spectral region.

The terahertz gap is a region of the electromagnetic spectrum where high average and peak power radiation sources are scarce while at the same time scientific and industrial applications are growing in demand. Free-electron laser (FEL) coupling in a magnetic undulator is one of the best options for radiation generation in this frequency range, but slippage effects require the use of relatively long

When solids are exposed to intense laser fields whose forces are comparable to the binding forces of valence electrons in crystals, nonlinear optics of solids advances to the nonperturbative or extreme nonlinear regime. A hallmark effect of extreme nonlinear optics is the emission of high-order harmonics of the laser from the bulk of materials. The discovery and detailed study of this phenomenon over

The chiral nature of phonons in crystals of biomolecules is identified by terahertz spectroscopy, paving the way to a better understanding of biochemical processes.

Researchers report a solid-state laser containing metasurfaces that generates a 10 × 10 array of phase-locked optical vortices with tunable orbital angular momentum.

Non-Abelian braiding, an essential process for realizing topological quantum computation, is implemented using an array of photonic integrated waveguides.

Materials displaying electron photoemission under visible-light excitation are of great interest for applications in photochemistry, photocathodes, advanced electron beam sources and electron microscopy. We demonstrate that in manganese-doped CdSe colloidal quantum dots (CQDs), two-step Auger up-conversion enables highly efficient electron photoemission under excitation with visible-light pulses. This

Non-reciprocal physical systems exhibit direction-dependent propagation of light, enabling a myriad of devices such as diodes and circulators. A new experiment demonstrates non-reciprocal amplification of light via atomic spins, driving photons on a one-way street through optical nanofibres.

In a non-reciprocal optical amplifier, gain depends on whether the light propagates forwards or backwards through the device. Typically, one requires either the magneto-optical effect, temporal modulation or optical nonlinearity to break reciprocity. By contrast, here we demonstrate non-reciprocal amplification of fibre-guided light using Raman gain provided by spin-polarized atoms that are coupled

Hong–Ou–Mandel (HOM) interference—the bunching of indistinguishable photons at a beamsplitter—is a staple of quantum optics and lies at the heart of many quantum sensing approaches and recent optical quantum computers. Here we report a full-field, scan-free quantum imaging technique that exploits HOM interference to reconstruct the surface depth profile of transparent samples. We demonstrate the ability

Geometric arrays of vortices found in various systems owe their regular structure to mutual interactions within a confined system. In optics, such vortex crystals may form spontaneously within a resonator. Their crystallization is relevant in many areas of physics, although their usefulness is limited by the lack of control over their topology. On the other hand, programmable devices like spatial light

The energy landscape of reduced-dimensional perovskites (RDPs) can be tailored by adjusting their layer width (n). Recently, two/three-dimensional (2D/3D) heterostructures containing n = 1 and 2 RDPs have produced perovskite solar cells (PSCs) with >25% power conversion efficiency (PCE). Unfortunately, this method does not translate to inverted PSCs due to electron blocking at the 2D/3D interface.

The interaction between structured light beams possessing optical angular momentum and small particles promises new opportunities for optical manipulation, such as the generation of light-induced torque and rotation of objects. However, so far, studies have largely centred on nanoscale particles. Here we report the observation and measurement of the transfer of transverse angular momentum to birefringent

Entanglement and spontaneous emission are fundamental quantum phenomena that drive many applications of quantum physics. During the spontaneous emission of light from an excited two-level atom, the atom briefly becomes entangled with the photonic field. Here we show that this natural process can be used to produce photon-number entangled states of light distributed in time. By exciting a quantum dot—an

The local polarization of light in nanophotonic waveguides changes with the light’s direction of propagation. By electrically controlling the polarization of optically created waveguide-coupled excitons in a two-dimensional semiconductor, researchers demonstrate voltage-controlled routing of photons in an integrated nanophotonic device.

A record-breaking microwave-to-optics conversion efficiency of 82% over a 1 MHz bandwidth for low photon numbers is achieved by using a gas of Rydberg atoms, paving the way towards applications in quantum technologies.

Halide perovskites are enticing candidates for highly efficient planar light-emitting diodes (LEDs) with commercial potential in displays and lighting. However, it remains a challenge for conventional solution fabrication processes to fabricate large-scale or non-planar LEDs due to the non-uniformity of perovskite films in conjunction with material stability issues. Here large-area highly uniform arrays

The formation of coherent macroscopic states and the manipulation of their entanglement using external stimuli are essential for emerging quantum applications. However, the observation of collective quantum phenomena such as Bose–Einstein condensation, superconductivity, superfluidity and superradiance has been limited to extremely low temperatures to suppress dephasing due to random thermal agitations

Non-Abelian braiding has attracted substantial attention because of its pivotal role in describing the exchange behaviour of anyons—candidates for realizing quantum logics. The input and outcome of non-Abelian braiding are connected by a unitary matrix that can also physically emerge as a geometric-phase matrix in classical systems. Hence it is predicted that non-Abelian braiding should have analogues

A photonic quantum memristor is experimentally demonstrated, paving the way to neuromorphic quantum computing.

Weak interaction of light with matter makes its tunable control notoriously challenging, resulting in bulky and inefficient devices. Now, a study demonstrates that van der Waals antiferromagnets featuring strong spin-charge induced anisotropy could offer excellent control of light polarization selectivity.

Optical birefringence is a fundamental optical property of crystals widely used for filtering and beam splitting of photons. Birefringent crystals concurrently possess the property of linear dichroism (LD), which allows asymmetric propagation or attenuation of light with two different polarizations. This property of LD has been widely studied from small molecules to polymers and crystals but has rarely

Memristive devices are a class of physical systems with history-dependent dynamics characterized by signature hysteresis loops in their input–output relations. In the past few decades, memristive devices have attracted enormous interest in electronics. This is because memristive dynamics is very pervasive in nanoscale devices, and has potentially groundbreaking applications ranging from energy-efficient

Chiral phonons are concerted mirror-symmetric movements of atomic groups connected by covalent and intermolecular bonds. Such lattice vibrations in crystals of biomolecules should be highly specific to their short- and long-range organizations, but their chiroptical signatures and structure–property relationships remain uncertain. Here we show that terahertz chiroptical spectroscopy enables the registration

Output power and beam quality are the two main bottlenecks for semiconductor lasers—the favourite light sources in countless applications because of their compactness, high efficiency and cheapness. Both limitations are due to the fact that it becomes increasingly harder to stabilize a single-mode laser over a broader chip area without multi-mode operations. Here we address this fundamental difficulty

Chiral nanophotonic interfaces enable propagation direction-dependent interactions between guided optical modes and circularly dichroic materials. Electrical tuning of interface chirality would aid active, switchable non-reciprocity in on-chip optoelectronic and photonic circuitry, but remains an outstanding challenge. Here, we report electrically controllable chirality in a nanophotonic interface

Harnessing birefringence in a photonic chip featuring an array of coupled waveguides brings new opportunities for investigating quantum effects such as bunching and antibunching.

Research on isolated attosecond pulses (IAPs) based on high-order harmonic generation changed substantially around 2010. Before then, the Ti:sapphire laser was the de facto standard as the driving light source, so the cutoff energy was limited to ~100 eV. After 2010, the mid-infrared optical parametric amplifier became the mainstream driving source. The shortest pulse width of an IAP has reached ~50 as

A liquid crystal doped with a diarylethene enantiomer can be switched by light into stable reflection states of different colour, creating new opportunities for lasing and labelling.

Dynamic patterning of soft materials in a fully reversible and programmable manner with light enables applications in anti-counterfeiting, displays and labelling technology. However, this is a formidable challenge due to the lack of suitable chiral molecular photoswitches. Here, we report the development of a unique intrinsic chiral photoswitch with broad chirality modulation to achieve digitally controllable

With the ever-growing demand for a greater number of pixels, next-generation displays have challenging requirements for resolution as well as colour gamut. Here, to meet this need, quantum-dot light-emitting diodes (QLEDs) with an ultrahigh pixel resolution of 9,072–25,400 pixels per inch are realized via transfer printing combined with the Langmuir–Blodgett film technology. To reduce the leakage current

Quantum transducers that can convert quantum signals from the microwave to the optical domain are a crucial optical interface for quantum information technology. Coherent microwave-to-optics conversions have been realized with various physical platforms, but all of them are limited to low efficiencies of less than 50%—the threshold of the no-cloning quantum regime. Here we report coherent microwave-to-optics

Blue phosphorescent organic light-emitting diodes (PhOLEDs) can deliver superior electroluminescence efficiencies than blue fluorescent OLEDs; however, their commercial debut has been delayed by short device lifetimes, especially for deep-blue PhOLEDs with Commission International de l’Eclairage y co-ordinates of less than 0.20. Here we report the use of new dopant and host materials to create a blue

The field of flat lens research brings innovative nanophotonic design concepts to the world of macro-optics. However, when evaluating the performance of these lenses a lack of consistency prevents proper comparison of competing technologies. This problem can be solved by using methods developed in industry for conventional lenses.

Entanglement and topology portray nature at the fundamental level but differently. Entangled states of particles are intrinsically sensitive to the environment, whereas the topological phases of matter are naturally robust against environmental perturbations. Harnessing topology to protect entanglement has great potential for reliable quantum applications. Generating topologically protected entanglement

Interferometry has been at the heart of wave optics since its early stages, resolving the coherence of the light field and enabling the complete reconstruction of the optical information it encodes. Transferring this concept to the attosecond time domain shed new light on fundamental ultrafast electron phenomena. Here we introduce attosecond-gated interferometry and probe one of the most fundamental